rrweb/packages/rrweb-snapshot/src/rebuild.ts

import { parse } from './css';
import {
  serializedNodeWithId,
  NodeType,
  tagMap,
  elementNode,
  BuildCache,
} from './types';
import { isElement, Mirror } from './utils';

const tagMap: tagMap = {
  script: 'noscript',
  // camel case svg element tag names
  altglyph: 'altGlyph',
  altglyphdef: 'altGlyphDef',
  altglyphitem: 'altGlyphItem',
  animatecolor: 'animateColor',
  animatemotion: 'animateMotion',
  animatetransform: 'animateTransform',
  clippath: 'clipPath',
  feblend: 'feBlend',
  fecolormatrix: 'feColorMatrix',
  fecomponenttransfer: 'feComponentTransfer',
  fecomposite: 'feComposite',
  feconvolvematrix: 'feConvolveMatrix',
  fediffuselighting: 'feDiffuseLighting',
  fedisplacementmap: 'feDisplacementMap',
  fedistantlight: 'feDistantLight',
  fedropshadow: 'feDropShadow',
  feflood: 'feFlood',
  fefunca: 'feFuncA',
  fefuncb: 'feFuncB',
  fefuncg: 'feFuncG',
  fefuncr: 'feFuncR',
  fegaussianblur: 'feGaussianBlur',
  feimage: 'feImage',
  femerge: 'feMerge',
  femergenode: 'feMergeNode',
  femorphology: 'feMorphology',
  feoffset: 'feOffset',
  fepointlight: 'fePointLight',
  fespecularlighting: 'feSpecularLighting',
  fespotlight: 'feSpotLight',
  fetile: 'feTile',
  feturbulence: 'feTurbulence',
  foreignobject: 'foreignObject',
  glyphref: 'glyphRef',
  lineargradient: 'linearGradient',
  radialgradient: 'radialGradient',
};
function getTagName(n: elementNode): string {
  let tagName = tagMap[n.tagName] ? tagMap[n.tagName] : n.tagName;
  if (tagName === 'link' && n.attributes._cssText) {
    tagName = 'style';
  }
  return tagName;
}

// based on https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#escaping
function escapeRegExp(str: string) {
  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}

const HOVER_SELECTOR = /([^\\]):hover/;
const HOVER_SELECTOR_GLOBAL = new RegExp(HOVER_SELECTOR.source, 'g');
export function addHoverClass(cssText: string, cache: BuildCache): string {
  const cachedStyle = cache?.stylesWithHoverClass.get(cssText);
  if (cachedStyle) return cachedStyle;

  const ast = parse(cssText, {
    silent: true,
  });

  if (!ast.stylesheet) {
    return cssText;
  }

  const selectors: string[] = [];
  ast.stylesheet.rules.forEach((rule) => {
    if ('selectors' in rule) {
      (rule.selectors || []).forEach((selector: string) => {
        if (HOVER_SELECTOR.test(selector)) {
          selectors.push(selector);
        }
      });
    }
  });

  if (selectors.length === 0) {
    return cssText;
  }

  const selectorMatcher = new RegExp(
    selectors
      .filter((selector, index) => selectors.indexOf(selector) === index)
      .sort((a, b) => b.length - a.length)
      .map((selector) => {
        return escapeRegExp(selector);
      })
      .join('|'),
    'g',
  );

  const result = cssText.replace(selectorMatcher, (selector) => {
    const newSelector = selector.replace(HOVER_SELECTOR_GLOBAL, '$1.\\:hover');
    return `${selector}, ${newSelector}`;
  });
  cache?.stylesWithHoverClass.set(cssText, result);
  return result;
}

export function createCache(): BuildCache {
  const stylesWithHoverClass: Map<string, string> = new Map();
  return {
    stylesWithHoverClass,
  };
}

function buildNode(
  n: serializedNodeWithId,
  options: {
    doc: Document;
    hackCss: boolean;
    cache: BuildCache;
  },
): Node | null {
  const { doc, hackCss, cache } = options;
  switch (n.type) {
    case NodeType.Document:
      return doc.implementation.createDocument(null, '', null);
    case NodeType.DocumentType:
      return doc.implementation.createDocumentType(
        n.name || 'html',
        n.publicId,
        n.systemId,
      );
    case NodeType.Element: {
      const tagName = getTagName(n);
      let node: Element;
      if (n.isSVG) {
        node = doc.createElementNS('http://www.w3.org/2000/svg', tagName);
      } else {
        node = doc.createElement(tagName);
      }
      for (const name in n.attributes) {
        if (!Object.prototype.hasOwnProperty.call(n.attributes, name)) {
          continue;
        }
        let value = n.attributes[name];
        if (tagName === 'option' && name === 'selected' && value === false) {
          // legacy fix (TODO: if `value === false` can be generated for other attrs,
          // should we also omit those other attrs from build ?)
          continue;
        }
        value =
          typeof value === 'boolean' || typeof value === 'number' ? '' : value;
        // attribute names start with rr_ are internal attributes added by rrweb
        if (!name.startsWith('rr_')) {
          const isTextarea = tagName === 'textarea' && name === 'value';
          const isRemoteOrDynamicCss =
            tagName === 'style' && name === '_cssText';
          if (isRemoteOrDynamicCss && hackCss) {
            value = addHoverClass(value, cache);
          }
          if (isTextarea || isRemoteOrDynamicCss) {
            const child = doc.createTextNode(value);
            // https://github.com/rrweb-io/rrweb/issues/112
            for (const c of Array.from(node.childNodes)) {
              if (c.nodeType === node.TEXT_NODE) {
                node.removeChild(c);
              }
            }
            node.appendChild(child);
            continue;
          }

          try {
            if (n.isSVG && name === 'xlink:href') {
              node.setAttributeNS('http://www.w3.org/1999/xlink', name, value);
            } else if (
              name === 'onload' ||
              name === 'onclick' ||
              name.substring(0, 7) === 'onmouse'
            ) {
              // Rename some of the more common atttributes from https://www.w3schools.com/tags/ref_eventattributes.asp
              // as setting them triggers a console.error (which shows up despite the try/catch)
              // Assumption: these attributes are not used to css
              node.setAttribute('_' + name, value);
            } else if (
              tagName === 'meta' &&
              n.attributes['http-equiv'] === 'Content-Security-Policy' &&
              name === 'content'
            ) {
              // If CSP contains style-src and inline-style is disabled, there will be an error "Refused to apply inline style because it violates the following Content Security Policy directive: style-src '*'".
              // And the function insertStyleRules in rrweb replayer will throw an error "Uncaught TypeError: Cannot read property 'insertRule' of null".
              node.setAttribute('csp-content', value);
              continue;
            } else if (
              tagName === 'link' &&
              n.attributes.rel === 'preload' &&
              n.attributes.as === 'script'
            ) {
              // ignore
            } else if (
              tagName === 'link' &&
              n.attributes.rel === 'prefetch' &&
              typeof n.attributes.href === 'string' &&
              n.attributes.href.endsWith('.js')
            ) {
              // ignore
            } else if (
              tagName === 'img' &&
              n.attributes.srcset &&
              n.attributes.rr_dataURL
            ) {
              // backup original img srcset
              node.setAttribute(
                'rrweb-original-srcset',
                n.attributes.srcset as string,
              );
            } else {
              node.setAttribute(name, value);
            }
          } catch (error) {
            // skip invalid attribute
          }
        } else {
          // handle internal attributes
          if (tagName === 'canvas' && name === 'rr_dataURL') {
            const image = document.createElement('img');
            image.onload = () => {
              const ctx = (node as HTMLCanvasElement).getContext('2d');
              if (ctx) {
                ctx.drawImage(image, 0, 0, image.width, image.height);
              }
            };
            image.src = value;
            type RRCanvasElement = {
              RRNodeType: NodeType;
              rr_dataURL: string;
            };
            // If the canvas element is created in RRDom runtime (seeking to a time point), the canvas context isn't supported. So the data has to be stored and not handled until diff process. https://github.com/rrweb-io/rrweb/pull/944
            if (((node as unknown) as RRCanvasElement).RRNodeType)
              ((node as unknown) as RRCanvasElement).rr_dataURL = value;
          } else if (tagName === 'img' && name === 'rr_dataURL') {
            const image = node as HTMLImageElement;
            if (!image.currentSrc.startsWith('data:')) {
              // Backup original img src. It may not have been set yet.
              image.setAttribute(
                'rrweb-original-src',
                n.attributes.src as string,
              );
              image.src = value;
            }
          }

          if (name === 'rr_width') {
            (node as HTMLElement).style.width = value;
          } else if (name === 'rr_height') {
            (node as HTMLElement).style.height = value;
          } else if (name === 'rr_mediaCurrentTime') {
            (node as HTMLMediaElement).currentTime = n.attributes
              .rr_mediaCurrentTime as number;
          } else if (name === 'rr_mediaState') {
            switch (value) {
              case 'played':
                (node as HTMLMediaElement)
                  .play()
                  .catch((e) => console.warn('media playback error', e));
                break;
              case 'paused':
                (node as HTMLMediaElement).pause();
                break;
              default:
            }
          }
        }
      }

      if (n.isShadowHost) {
        /**
         * Since node is newly rebuilt, it should be a normal element
         * without shadowRoot.
         * But if there are some weird situations that has defined
         * custom element in the scope before we rebuild node, it may
         * register the shadowRoot earlier.
         * The logic in the 'else' block is just a try-my-best solution
         * for the corner case, please let we know if it is wrong and
         * we can remove it.
         */
        if (!node.shadowRoot) {
          node.attachShadow({ mode: 'open' });
        } else {
          while (node.shadowRoot.firstChild) {
            node.shadowRoot.removeChild(node.shadowRoot.firstChild);
          }
        }
      }
      return node;
    }
    case NodeType.Text:
      return doc.createTextNode(
        n.isStyle && hackCss
          ? addHoverClass(n.textContent, cache)
          : n.textContent,
      );
    case NodeType.CDATA:
      return doc.createCDATASection(n.textContent);
    case NodeType.Comment:
      return doc.createComment(n.textContent);
    default:
      return null;
  }
}

export function buildNodeWithSN(
  n: serializedNodeWithId,
  options: {
    doc: Document;
    mirror: Mirror;
    skipChild?: boolean;
    hackCss: boolean;
    afterAppend?: (n: Node, id: number) => unknown;
    cache: BuildCache;
  },
): Node | null {
  const {
    doc,
    mirror,
    skipChild = false,
    hackCss = true,
    afterAppend,
    cache,
  } = options;
  let node = buildNode(n, { doc, hackCss, cache });
  if (!node) {
    return null;
  }
  if (n.rootId) {
    console.assert(
      (mirror.getNode(n.rootId) as Document) === doc,
      'Target document should have the same root id.',
    );
  }
  // use target document as root document
  if (n.type === NodeType.Document) {
    // close before open to make sure document was closed
    doc.close();
    doc.open();
    if (
      n.compatMode === 'BackCompat' &&
      n.childNodes &&
      n.childNodes[0].type !== NodeType.DocumentType // there isn't one already defined
    ) {
      // Trigger compatMode in the iframe
      // this is needed as document.createElement('iframe') otherwise inherits a CSS1Compat mode from the parent replayer environment
      if (
        n.childNodes[0].type === NodeType.Element &&
        'xmlns' in n.childNodes[0].attributes &&
        n.childNodes[0].attributes.xmlns === 'http://www.w3.org/1999/xhtml'
      ) {
        // might as well use an xhtml doctype if we've got an xhtml namespace
        doc.write(
          '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">',
        );
      } else {
        doc.write(
          '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "">',
        );
      }
    }
    node = doc;
  }

  mirror.add(node, n);

  if (
    (n.type === NodeType.Document || n.type === NodeType.Element) &&
    !skipChild
  ) {
    for (const childN of n.childNodes) {
      const childNode = buildNodeWithSN(childN, {
        doc,
        mirror,
        skipChild: false,
        hackCss,
        afterAppend,
        cache,
      });
      if (!childNode) {
        console.warn('Failed to rebuild', childN);
        continue;
      }

      if (childN.isShadow && isElement(node) && node.shadowRoot) {
        node.shadowRoot.appendChild(childNode);
      } else {
        node.appendChild(childNode);
      }
      if (afterAppend) {
        afterAppend(childNode, childN.id);
      }
    }
  }

  return node;
}

function visit(mirror: Mirror, onVisit: (node: Node) => void) {
  function walk(node: Node) {
    onVisit(node);
  }

  for (const id of mirror.getIds()) {
    if (mirror.has(id)) {
      walk(mirror.getNode(id)!);
    }
  }
}

function handleScroll(node: Node, mirror: Mirror) {
  const n = mirror.getMeta(node);
  if (n?.type !== NodeType.Element) {
    return;
  }
  const el = node as HTMLElement;
  for (const name in n.attributes) {
    if (
      !(
        Object.prototype.hasOwnProperty.call(n.attributes, name) &&
        name.startsWith('rr_')
      )
    ) {
      continue;
    }
    const value = n.attributes[name];
    if (name === 'rr_scrollLeft') {
      el.scrollLeft = value as number;
    }
    if (name === 'rr_scrollTop') {
      el.scrollTop = value as number;
    }
  }
}

function rebuild(
  n: serializedNodeWithId,
  options: {
    doc: Document;
    onVisit?: (node: Node) => unknown;
    hackCss?: boolean;
    afterAppend?: (n: Node, id: number) => unknown;
    cache: BuildCache;
    mirror: Mirror;
  },
): Node | null {
  const {
    doc,
    onVisit,
    hackCss = true,
    afterAppend,
    cache,
    mirror = new Mirror(),
  } = options;
  const node = buildNodeWithSN(n, {
    doc,
    mirror,
    skipChild: false,
    hackCss,
    afterAppend,
    cache,
  });
  visit(mirror, (visitedNode) => {
    if (onVisit) {
      onVisit(visitedNode);
    }
    handleScroll(visitedNode, mirror);
  });
  return node;
}

export default rebuild;